Tantalum is a chemically stable metal and therefore used for various uses. For example, tantalum is widely used as a capacitor material for electronic instruments such as cellular phone and personal computer. The tantalum used as a capacitor material is usually in the powder shape and the powder particles are molded and then integrated by sintering to provide an electrode called a sintered body. The inside of the sintered body has a three-dimensional complicated form where the powder particles are electrically/mechanically connected. In the inside and outside of this sintered body, a dielectric film layer is formed and then a material working out to a counter electrode is impregnated, thereby fabricating a capacitor. Microscopically, the capacitance of the manufactured capacitor greatly depends on the contact state between the counter electrode material and the dielectric film layer insofar as the dielectric film layer is uniformly attached to the surface inside and outside the sintered body.